bnx2x: Fix VF MAC removal

There's a bug in today's driver where VF requests to add/remove MAC filters
always reach the Hypervisor as add requests.
This prevents the VF from changing its MAC address, as it cannot remove the
previously configured MAC and runs out of MAC credits.

Signed-off-by: Shahed Shaikh <Shahed.Shaikh@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>